RFID tags are well known in the art and generally comprise an electrical circuit having an antenna connected to an integrated circuit (RFID chip or module). The transponder is responsive to a received radio frequency signal and produces a radio frequency signal.
Beside the connection of the two electric elements of the electrical circuit, a key step of the manufacture of a transponder is the encapsulation of said electrical circuit in order to protect it from mechanical shocks, from soiling, fluids, heat, . . . to ensure a durable mechanical connection between the two elements and to provide a size that allows for better handling.
To ensure perfect functionality of the transponder, the packaging has to be totally adapted to the nature of the final application and to the specifications defined by the user. The final product can be—but is not limited to—a glass mini-tube, a plastic coin token or a contactless smart card. Due to the popularity of the RFID technology in an increasing number of fields of activity, there are more and more demands for special types of packaging.
It is therefore an object of the present invention to provide an RFID tag with a high resistance to flexion stress. Such tag would be very suitable for example for laundry applications wherein solid un-flexible bodies are not desired.
The applicant has already proposed a flexible tag for laundry application in the patent application DE102004027978. It discloses a smart laundry label wherein the transponder is maintained floating in a soft adhesive between two cover sheets. This structure ensures a very high flexibility as well as a good protection of the chip and antenna as they are freely floating in a semi-liquid material. This solution has however multiple drawbacks. The handling of large quantity of soft adhesive material is not very appropriate for high volume manufacturing (costly and dirty). The fact that the antenna and the chip are also not fixed to any support structure is also a source of weakness for example in regard of extreme bending wherein the entire efforts will directly apply to these active components (or their connection). Such a tag shows also a poor resistance to mechanical impact.